OBJECTIVES： The aim of this randomized, parallel-group, double-blinded controlled multicenter clinical trial is to determine the proper dosage of botulinum toxin type A in Asian, and provide evidence-based proof.

METHODS: 250 patients were included in this study, first, trained observers assessed their wrinkle severity according to the 5-grade Wrinkle Severity Rating Scale before injecting botulinum toxin type A, then we injected different dosages to patients with the different pre-injection scores. All patients were followed up for up to one year. Logistic regression was built, the chi-square test was performed, and R square and p-value are used for evaluation.

This was a self-reported, randomized, parallel-group, double-blinded controlled multicenter clinical trial. It was conducted in Wuhan, Shanghai, and Dongguan, China, at the plastic and reconstructive surgery, and approved by the ethics committee of Shanghai Ninth People's Hospital, affiliated to Shanghai Jiao Tong University School of Medicine. All patients were fully informed about the study in accordance with the applicable regulations and International Conference on Harmonisation Good Clinical Practices guidelines and gave written informed consent before the study. The main inclusion criteria were: 1. Chinese males or females aged over 18 years old who want to accept medical removal of the wrinkle; 2. noticeable symmetrical wrinkles on both sides of the face (grade 1-4 on the 5-grade Wrinkles Severity Rating Scale); 3. female patients must take a pregnancy test to prove they are not pregnant, and they are also asked to use a method of contraception 30 days before inclusion into the group and to use a reliable method of contraception throughout the entire study; 4. patients should not accept other forms of cosmetic intervention and agree to refrain from participation in any other clinical trials that may interrupt the study. The main exclusion criteria were: 1. the wrinkle severity of any site or both sites are either grade 0 or 5 on the 5-grade Wrinkle Severity Rating Scale. 2. the presence of facial hair that may influence the observation of wrinkle severity; 3. the area of injection had an apparent acne scar, active inflammation, infection, cancer or premalignancy, or untreated wound; 4. patients who had facial plastic surgery, tissue transplant, silica gel, liposome (fat) injection, or other permanent or semi-permanent dermal filler; 5. patients who had any type of Botox injection in the last year or were injected more than 3 times.

Inclusion Criteria:

• 1. Chinese males or females aged over 18 years old who want to accept medical removal of the wrinkle;
• 2. Noticeable symmetrical wrinkles on both sides of the face (grade 1-4 on the 5-grade Wrinkles Severity Rating Scale);
• 3. Female patients must take a pregnancy test to prove they are not pregnant, and they are also asked to use a method of contraception 30 days before inclusion into the group and to use a reliable method of contraception throughout the entire study;
• 4. Patients should not accept other forms of cosmetic intervention and agree to refrain from participation in any other clinical trials that may interrupt the study.

Exclusion Criteria:

• 1. The wrinkle severity of any site or both sites are either grade 0 or 5 on the 5-grade Wrinkle Severity Rating Scale.
• 2. The presence of facial hair that may influence the observation of wrinkle severity;
• 3. The area of injection had an apparent acne scar, active inflammation, infection, cancer or premalignancy, or untreated wound;
• 4. Patients who had facial plastic surgery, tissue transplant, silica gel, liposome (fat) injection, or other permanent or semipermanent dermal filler;
• 5. Patients who had any type of Botox injection in the last year or were injected more than 3 times.

the status of the participents